X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=pack-objects.c;h=3d622787cc554eb2936995441e4591ec1986bded;hb=4fa2197e614950279527b14825d1e9572454a48c;hp=e9764604f6f17f4eb018b4fd7247550e90583f8c;hpb=d22b9290ab6de119d03154844910ae5d963b5f1f;p=git.git

diff --git a/pack-objects.c b/pack-objects.c
index e9764604..3d622787 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -2,29 +2,25 @@
 #include "cache.h"
 #include "object.h"
 #include "delta.h"
+#include "pack.h"
 #include "csum-file.h"
 
-static const char pack_usage[] = "git-pack-objects [--window=N] [--depth=N] {--stdout | base-name} < object-list";
+static const char pack_usage[] = "git-pack-objects [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
-/*
- * The object type is a single-character shorthand:
- *  - 'C' for "Commit"
- *  - 'T' for "Tree"
- *  - 'B' for "Blob"
- *  - 'G' for "taG"
- *  - 'D' for "Delta"
- */
 struct object_entry {
 	unsigned char sha1[20];
 	unsigned long size;
 	unsigned long offset;
 	unsigned int depth;
 	unsigned int hash;
-	unsigned char type;
+	enum object_type type;
 	unsigned long delta_size;
 	struct object_entry *delta;
 };
 
+static unsigned char object_list_sha1[20];
+static int non_empty = 0;
+static int incremental = 0;
 static struct object_entry **sorted_by_sha, **sorted_by_type;
 static struct object_entry *objects = NULL;
 static int nr_objects = 0, nr_alloc = 0;
@@ -41,7 +37,7 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
 	if (!otherbuf)
 		die("unable to read %s", sha1_to_hex(entry->delta->sha1));
         delta_buf = diff_delta(otherbuf, othersize,
-			       buf, size, &delta_size, ~0UL);
+			       buf, size, &delta_size, 0);
         if (!delta_buf || delta_size != entry->delta_size)
         	die("delta size changed");
         free(buf);
@@ -49,13 +45,41 @@ static void *delta_against(void *buf, unsigned long size, struct object_entry *e
 	return delta_buf;
 }
 
+/*
+ * The per-object header is a pretty dense thing, which is
+ *  - first byte: low four bits are "size", then three bits of "type",
+ *    and the high bit is "size continues".
+ *  - each byte afterwards: low seven bits are size continuation,
+ *    with the high bit being "size continues"
+ */
+static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
+{
+	int n = 1;
+	unsigned char c;
+
+	if (type < OBJ_COMMIT || type > OBJ_DELTA)
+		die("bad type %d", type);
+
+	c = (type << 4) | (size & 15);
+	size >>= 4;
+	while (size) {
+		*hdr++ = c | 0x80;
+		c = size & 0x7f;
+		size >>= 7;
+		n++;
+	}
+	*hdr = c;
+	return n;
+}
+
 static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
 {
 	unsigned long size;
 	char type[10];
 	void *buf = read_sha1_file(entry->sha1, type, &size);
-	char header[25];
+	unsigned char header[10];
 	unsigned hdrlen, datalen;
+	enum object_type obj_type;
 
 	if (!buf)
 		die("unable to read %s", sha1_to_hex(entry->sha1));
@@ -63,43 +87,64 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry
 		die("object %s size inconsistency (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
 
 	/*
-	 * The object header is a byte of 'type' followed by four bytes of
-	 * length, except for deltas that has the 20 bytes of delta sha
-	 * instead.
+	 * The object header is a byte of 'type' followed by zero or
+	 * more bytes of length.  For deltas, the 20 bytes of delta sha1
+	 * follows that.
 	 */
-	header[0] = entry->type;
-	hdrlen = 5;
+	obj_type = entry->type;
 	if (entry->delta) {
-		header[0] = 'D';
-		memcpy(header+5, entry->delta, 20);
 		buf = delta_against(buf, size, entry);
 		size = entry->delta_size;
-		hdrlen = 25;
+		obj_type = OBJ_DELTA;
 	}
-	datalen = htonl(size);
-	memcpy(header+1, &datalen, 4);
+	hdrlen = encode_header(obj_type, size, header);
 	sha1write(f, header, hdrlen);
+	if (entry->delta) {
+		sha1write(f, entry->delta, 20);
+		hdrlen += 20;
+	}
 	datalen = sha1write_compressed(f, buf, size);
 	free(buf);
 	return hdrlen + datalen;
 }
 
+static unsigned long write_one(struct sha1file *f,
+			       struct object_entry *e,
+			       unsigned long offset)
+{
+	if (e->offset)
+		/* offset starts from header size and cannot be zero
+		 * if it is written already.
+		 */
+		return offset;
+	e->offset = offset;
+	offset += write_object(f, e);
+	/* if we are delitified, write out its base object. */
+	if (e->delta)
+		offset = write_one(f, e->delta, offset);
+	return offset;
+}
+
 static void write_pack_file(void)
 {
 	int i;
 	struct sha1file *f;
-	unsigned long offset = 0;
+	unsigned long offset;
 	unsigned long mb;
+	struct pack_header hdr;
 
 	if (!base_name)
 		f = sha1fd(1, "<stdout>");
 	else
-		f = sha1create("%s.%s", base_name, "pack");
-	for (i = 0; i < nr_objects; i++) {
-		struct object_entry *entry = objects + i;
-		entry->offset = offset;
-		offset += write_object(f, entry);
-	}
+		f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack");
+	hdr.hdr_signature = htonl(PACK_SIGNATURE);
+	hdr.hdr_version = htonl(PACK_VERSION);
+	hdr.hdr_entries = htonl(nr_objects);
+	sha1write(f, &hdr, sizeof(hdr));
+	offset = sizeof(hdr);
+	for (i = 0; i < nr_objects; i++)
+		offset = write_one(f, objects + i, offset);
+
 	sha1close(f, pack_file_sha1, 1);
 	mb = offset >> 20;
 	offset &= 0xfffff;
@@ -108,7 +153,7 @@ static void write_pack_file(void)
 static void write_index_file(void)
 {
 	int i;
-	struct sha1file *f = sha1create("%s.%s", base_name, "idx");
+	struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
 	struct object_entry **list = sorted_by_sha;
 	struct object_entry **last = list + nr_objects;
 	unsigned int array[256];
@@ -145,11 +190,14 @@ static void write_index_file(void)
 	sha1close(f, NULL, 1);
 }
 
-static void add_object_entry(unsigned char *sha1, unsigned int hash)
+static int add_object_entry(unsigned char *sha1, unsigned int hash)
 {
 	unsigned int idx = nr_objects;
 	struct object_entry *entry;
 
+	if (incremental && has_sha1_pack(sha1))
+		return 0;
+
 	if (idx >= nr_alloc) {
 		unsigned int needed = (idx + 1024) * 3 / 2;
 		objects = xrealloc(objects, needed * sizeof(*entry));
@@ -160,6 +208,7 @@ static void add_object_entry(unsigned char *sha1, unsigned int hash)
 	memcpy(entry->sha1, sha1, 20);
 	entry->hash = hash;
 	nr_objects = idx+1;
+	return 1;
 }
 
 static void check_object(struct object_entry *entry)
@@ -168,13 +217,13 @@ static void check_object(struct object_entry *entry)
 
 	if (!sha1_object_info(entry->sha1, type, &entry->size)) {
 		if (!strcmp(type, "commit")) {
-			entry->type = 'C';
+			entry->type = OBJ_COMMIT;
 		} else if (!strcmp(type, "tree")) {
-			entry->type = 'T';
+			entry->type = OBJ_TREE;
 		} else if (!strcmp(type, "blob")) {
-			entry->type = 'B';
+			entry->type = OBJ_BLOB;
 		} else if (!strcmp(type, "tag")) {
-			entry->type = 'G';
+			entry->type = OBJ_TAG;
 		} else
 			die("unable to pack object %s of type %s",
 			    sha1_to_hex(entry->sha1), type);
@@ -333,10 +382,15 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		if (idx >= window)
 			idx = 0;
 	}
+
+	for (i = 0; i < window; ++i)
+		free(array[i].data);
+	free(array);
 }
 
 int main(int argc, char **argv)
 {
+	SHA_CTX ctx;
 	char line[PATH_MAX + 20];
 	int window = 10, depth = 10, pack_to_stdout = 0;
 	int i;
@@ -345,6 +399,14 @@ int main(int argc, char **argv)
 		const char *arg = argv[i];
 
 		if (*arg == '-') {
+			if (!strcmp("--non-empty", arg)) {
+				non_empty = 1;
+				continue;
+			}
+			if (!strcmp("--incremental", arg)) {
+				incremental = 1;
+				continue;
+			}
 			if (!strncmp("--window=", arg, 9)) {
 				char *end;
 				window = strtoul(arg+9, &end, 0);
@@ -373,6 +435,7 @@ int main(int argc, char **argv)
 	if (pack_to_stdout != !base_name)
 		usage(pack_usage);
 
+	SHA1_Init(&ctx);
 	while (fgets(line, sizeof(line), stdin) != NULL) {
 		unsigned int hash;
 		char *p;
@@ -388,8 +451,12 @@ int main(int argc, char **argv)
 				continue;
 			hash = hash * 11 + c;
 		}
-		add_object_entry(sha1, hash);
+		if (add_object_entry(sha1, hash))
+			SHA1_Update(&ctx, sha1, 20);
 	}
+	SHA1_Final(object_list_sha1, &ctx);
+	if (non_empty && !nr_objects)
+		return 0;
 	get_object_details();
 
 	fprintf(stderr, "Packing %d objects\n", nr_objects);
@@ -400,7 +467,9 @@ int main(int argc, char **argv)
 		find_deltas(sorted_by_type, window+1, depth);
 
 	write_pack_file();
-	if (!pack_to_stdout)
+	if (!pack_to_stdout) {
 		write_index_file();
+		puts(sha1_to_hex(object_list_sha1));
+	}
 	return 0;
 }